This invention relates to a sofa sleeper and, more particularly, to a sofa sleeper of the type which includes a foldable bed having head, body, intermediate and foot sections which are foldable and which may be collapsed and hidden in the bottom of the sofa frame when the sofa sleeper is used as a seating surface.
Sofa sleeper mechanisms generally comprise a four-section foldable bed frame including pivotally interconnected head, body, intermediate and foot sections which are adapted to be moved between a fully folded or retracted position contained within a box-like sofa frame, and an extended position wherein the sections extend out and over the front rail of the sofa frame to form an extended flat bed. The head, body, intermediate and foot sections of the bed frame each include a pair of opposed side frame members, usually in the form of angles or tubes, which are pivotally connected at their ends so that the sections are foldable or collapsible upon one another. The side frame members support a link or cloth fabric over which a mattress is placed. The bed frame is supported when in the extended bed position by linkage mechanisms at the head end and by a plurality of foldable legs at the center and foot end of the frame.
A common problem characteristic of sofa sleepers is that when folded out into the flat bed sleeping position, they are subject to tilting about the linkage mechanism which supports the foldable bed frame from the wooden sofa frame. Such tilting occurs when excessive weight is applied to the head section of the sofa sleeper. In that event, the foot end of the sofa sleeper tips up in the air, and the head end tips downwardly. This phenomena commonly occurs whenever one or more persons sit on the head end of the unfolded sofa-sleeper mechanism, as for example, to watch TV, or if a person stands on the head end of the unfolded bed, as for example, to adjust curtains behind the bed. In either event, the head end of the unfolded sleeper mechanism drops down while the foot end lifts upwardly, thereby dropping the person whose weight is causing the mechanism to tilt down into the cavity of the wooden sofa frame. Manifestly, such tilting is undesirable.
There have been sofa sleeper mechanisms which included a locking mechanism for preventing tilting of the sofa-sleeper mechanism when in the unfolded condition. Such prior art mechanisms are characterized by multiple link locking mechanisms, as for example, the anti-tilt locking mechanism disclosed in Gerth U.S. Pat. No. 3,292,188. The difficulty with such anti-tilt locking mechanisms is that they all require multiple links or linkage elements to effect the lock and are all subject to criticism because of the added expense those multiple link locking mechanisms add to the sofa-sleeper mechanism. They are also subject to failure in the event that the linkages bend or the pivots about which the multiple links are mounted become worn or broken.
It has therefore been an objective of this invention to provide an improved anti-tilt sofa-sleeper mechanism which does not utilize multiple links and which is much less expensive to add to a sofa-sleeper mechanism than the multiple link locking mechanisms of the prior art.
This objective is accomplished and this invention is predicated upon the concept of connecting an anti-tilt, flexible, non-stretchable cable between two locations on the mechanism such that the cable is taut when the mechanism is unfolded to a bed position, in which taut position it will prevent the unfolded mechanism from tilting to drop the head end of the unfolded mechanism, and which cable will become relaxed or coiled and not interfere with folding of the mechanism when the mechanism is folded into the sofa frame.